Skip to content
Fencer Vulns
medium 5.7

CVE-2018-16841 json

Samba from version 4.3.0 and before versions 4.7.12, 4.8.7 and 4.9.3 are vulnerable to a denial of service.

published 2018-11-28 7 y ago modified 2026-06-17 4 mo ago also EUVD-2018-8637

cvss
5.7
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
4.6%
EPSS 4.6% chance of exploitation in 30 days, percentile 91%
public exploits
0
none known

Summary

Samba from version 4.3.0 and before versions 4.7.12, 4.8.7 and 4.9.3 are vulnerable to a denial of service. When configured to accept smart-card authentication, Samba's KDC will call talloc_free() twice on the same memory if the principal in a validly signed certificate does not match the principal in the AS-REQ. This is only possible after authentication with a trusted certificate. talloc is robust against further corruption from a double-free with talloc_free() and directly calls abort(), terminating the KDC process.

Patch / fix

  • samba samba 4.7.12, 4.8.7, 4.9.3
  • samba Debian 14, Debian 13, Debian 12 2:4.9.2+dfsg-2

debian advisories DEBIAN-CVE-2018-16841

  • samba Ubuntu 14.04 LTS 2:4.3.11+dfsg-0ubuntu0.14.04.19
  • samba Ubuntu 16.04 LTS 2:4.3.11+dfsg-0ubuntu0.16.04.18
  • samba Ubuntu 18.04 LTS 2:4.7.6+dfsg~ubuntu-0ubuntu2.5

ubuntu advisories UBUNTU-CVE-2018-16841

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • samba SLE Module for Package Hub 15, SLE Module for Basesystem 15, SLE High Availability Extension 15 4.7.11+git.140.6bd0e5b30d8-4.21.1

suse advisories SUSE-SU-2018:4066-1

  • samba openSUSE Tumbleweed 4.14.6+git.182.2205d5224e3-1.1

opensuse advisories openSUSE-SU-2024:11365-1

  • samba Alpine 3.24, Alpine 3.23, Alpine 3.22 +13 more 4.8.7-r0
  • samba Alpine 3.6 4.6.16-r2
  • samba Alpine 3.7 4.7.6-r2
  • samba Alpine 3.8 4.8.8-r0

alpine advisories ALPINE-CVE-2018-16841

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • samba Arch Linux 4.9.3-1

arch linux advisories AVG-823

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2018-16841 updated cvss 5.7

samba: Double-free in Samba AD DC KDC with PKINIT

  • Red Hat Enterprise Linux 6 samba4, samba4-dc, samba4-libs, samba4-pidl, samba4-swat, samba4-test, +7 more Red Hat Enterprise Linux 7 ctdb, samba, samba-dc, ctdb-tests, samba-libs, samba-pidl, +18 more Red Hat Enterprise Linux 8 ctdb, samba, libnetapi, ctdb-tests, samba-libs, samba-pidl, +24 more Red Hat Storage 3 ctdb, samba, samba-dc, ctdb-tests, samba-libs, samba-pidl, +21 more Red Hat Virtualization 4 samba
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

4.59% chance of exploitation in the next 30 days, higher than 91% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.0 5.7 CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 4.0 AV:N/AC:L/Au:S/C:N/I:N/A:P

Affected products

  • [UNKNOWN] samba

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.